Vehicular impact absorbing apparatus having cushion pins

ABSTRACT

A vehicular impact absorbing apparatus is disclosed. The apparatus includes a pair of tubular guide rails having a guide slit longitudinally formed at the upper part of each guide rail fixed to the ground. A plurality of sliders are movably mounted in the guide rail at a predetermined intervals, the upper part of each slider is laid on the upper part of the guide rail through the guide slit. A plurality of cushion units are mounted on the upper part of each slider. Each cushion unit is elastically deformed by vehicular impacts with retracting alongside the guide rail. A group of cushion pins are mounted across the guide rails at predetermined intervals between the sliders. The cushion pins also absorb the kinetic energy of an impact by being broken in turn by the slider that is retracting rearward. A stopper is installed around the rear end of the guide rail for stopping the retracting cushion units. A side fence is retractably mounted alongside the cushion units; the one end of the side fence is fixed to the stopper and the other to the front cushion unit. A successive cushion and deceleration of the impacts is possible in this arrangement.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a safety guard installed on a roadway at which a vehicular impact is expected, and more particularly to a vehicular impact absorbing apparatus having cushion pins, which ensures an effective arrest of vehicle impacts.

[0003] 2. Description of the Prior Art

[0004] In general, there are installed various roadway safety facilities, for example, guard rails for protecting vehicles from deviating from the road and median dividers for preventing intrusion of a vehicle into the opposite lane. Further, safety guards or crash cushions are installed alongside roadways in front of obstructions such as concrete walls, the ends of dividers, toll booths and the like for protecting them against a vehicular impact as well as passengers from a car crash.

[0005] The guard rail and the median divider seldom collide head-on with a vehicle as they are disposed along by the road. However, the safe guard is apt to collide head-on with vehicles since it is located front the driving direction.

[0006] In the event of a head-on collision with the safe guard, enormous impact energy is applied to the vehicle which results in a fatal blow to the vehicle and passenger. Therefore, it is desirable that the safe guard effectively absorbs the kinetic energy of an impacting vehicle to minimize injury of passengers and to reduce damages of roadway facilities as well as the vehicle.

[0007] Common type of the safety guard is formed by a concrete structure or a cushion using worn tires or polyurethane foam. The safety guard of concrete structure may protect roadway facilities with simple construction at low cost, however it can not absorb vehicular impacts at all. As a result, it presents a serious roadway hazard to vehicles. In the case of the cushion safety guard, it is good at absorbing impact energy, however it returns the impact energy as repulsive power which sends the impacting vehicle back into traffic at a steep angle. This may cause secondary collision on the roadway with another vehicle.

[0008] To overcome these problems of the conventional safety guard, various kind of vehicular impact absorbing apparatus have been proposed, for example, in Korean Patent No. 0348707, U.S. Pat. No. 5,868,521, and PCT International Publication No. WO 00/52267,

[0009] Korean Patent No. 0348707 discloses a vehicular impact absorbing apparatus having an array of rubber barrels filled with a cushioning material. Rubber barrels are supported by a steel plates buried in each barrel and slidably mounted on a single centered rail. The barrels following the front barrel are provided at inner side thereof with a wave-shaped steel plate. The rear end of barrel array is fixed to a roadway obstruction by anchor bolts. In a crash, the barrels are retracted along the rail and compressive transformed to absorb the kinetic energy of an impacting vehicle. The wave-shaped steel plate restrains the repulsive force resulting from the impact energy.

[0010] However, since the cushioning simply depends on the physical transformation of the cushioning material, the cushioning effect may be affected by the characteristics of the cushioning material, and it is difficult to fully cushion several tens tons of the kinetic energy.

[0011] Although this may be overcome by extending the length of the barrel array, it may be limited by conditions of the roadway. Further, since the barrel array is fixed to the concrete wall, it can not be installed at the location where concrete wall does not exist such as the ends of median dividers and the front of simple branch road.

[0012] U.S. Pat. No. 5,868,521 discloses a highway crash cushion includes an array of diaphragms each of which has a guide slidably mounted on a single central guide rail, a plurality of energy absorbing elements disposed between the diaphragms, and an array of fender panels extending alongside the diaphragms. In axial collapse, the diaphragms move closer to on another, the fender panels telescope over one another, and the energy absorbing elements are compressed. Since this crash cushion also absorbs the kinetic energy of an impacting vehicle as the crash cushion collapses axially, it may require a considerable axial length of the crash cushion in order to absorb several hundreds tons of the kinetic energy. Also, it needs a great deal of cost to repair and rebuild the energy absorbing elements following a collision.

[0013] PCT Publication WO 00/52267 discloses a crash cushion formed by a pipe rack frame that retains a number of axially disposed cushion barrels. The pipe frame is provided with a slider which constrain the barrels. The barrels are crushed to absorb a vehicular impact. Such a crash cushion is also difficult to fully absorb several tens tons of the impact energy.

SUMMARY OF THE INVENTION

[0014] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a vehicular impact absorbing apparatus which can effectively absorb the kinetic energy of an impacting vehicle.

[0015] Another object of the present invention is to provide a vehicular impact absorbing apparatus which is free from the restraint of installation due to roadway conditions.

[0016] A further object of the present invention is to provide a vehicular impact absorbing apparatus which prevents spring back of an impacting vehicle due to the repulsive power thereof.

[0017] A further object of the present invention is to provide a vehicular impact absorbing apparatus which utilizes disused resources as a cushion element and saves installation cost.

[0018] A further object of the present invention is to provide a vehicular impact absorbing apparatus which can be quickly rebuilt following a collision and reduce coat to repair and rebuild the apparatus.

[0019] In order to accomplish the above object, the present invention resides in a vehicular impact absorbing apparatus, which comprises; a tubular guide rail having a guide slit longitudinally formed at the upper part of the guide rail, the guide rail being fixed to the ground; a plurality of sliders movably mounted in the guide rail at a predetermined intervals, the upper part of each slider being laid on the upper part of the guide rail through the guide slit; a plurality of cushion units mounted on the upper part of each slider, each cushion unit being elastically, deformed by vehicular impacts with retracting alongside the guide rail; a group of cushion pins mounted across the guide rail at a predetermined intervals located between the sliders, the cushion pins being broken serially by the slider which is retracting rearward; a stopper installed around the rear end of the guide rail for stopping the retracting cushion units; and a side fence retractably mounted alongside the cushion units, the one end of the side fence being fixed to the stopper and the other to the front cushion unit.

[0020] In accordance with a preferred feature of this invention, the cushion unit includes a base plate mounted on the top portion of the slider, the base plate having a supports fixed thereto and vertically extended along the side portion of the cushion unit; a cushion element loaded onto the supports of the base plate with a part of the cushion element being protruded from the front and rear side of the base plate; and a holding cover coupled to the below portion of the base plate and the top portion of the support, for surrounding both sides of the cushion element. For example, the cushion element includes a stack of worn tires being laid around the support.

[0021] In accordance with a preferred feature of this invention, the guide rail is formed with a plurality of fastening holes for receiving the cushion pins, and the fastening holes is formed in two rows such that the holes in each row to cross each other.

[0022] In accordance with a preferred feature of this invention, the apparatus further comprises an outer cover for enclosing the components of the apparatus, the outer cover includes a plurality of middle covers coupled to each cushion unit for covering the cushion units, a front cover coupled to the foremost middle cover for covering the front portion of the foremost cushion unit, and a rear cover for covering the stopper, the covers being coupled to telescope over one another.

[0023] By the vehicular impact absorbing apparatus according to the present invention, an effective absorption of the kinetic energy of an impacting vehicle is possible through an appropriate elastic deformation of the cushion units and a successive shear of the cushion pins.

[0024] Further, since the sliders are interfered by the broken cushion pins after passing through the cushion pins, it is possible to prevent spring back of the cushion elements due to the repulsive power thereof and to stop the movement of the impacting vehicle. This contributes to a protection of the impacting vehicle against the secondary collision with another vehicle.

[0025] Furthermore, since the amount of compress deformation of the cushion elements is increased as proceeding to rearward, a successive cushion and deceleration of the vehicular impact is possible, thereby absorbing the minute impact energy and minimizing the effect of the impact on the passenger.

[0026] In addition, since the cushion units are elastically deformed as they moves along the guide rails, the cushion units can be reused and simple replacing operation of the broken cushion pins is required. This contributes to reduction in maintenance and repair cost,

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0028]FIG. 1 is a perspective view of a vehicular impact absorbing apparatus according to the present invention;

[0029]FIG. 2 is a partial exploded perspective view of the vehicular impact absorbing apparatus shown in FIG. 1, with its cover removed from the apparatus;

[0030]FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1;

[0031]FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3;

[0032]FIG. 5 is an exploded perspective view of a slide cushion unit extracted from the apparatus of the present invention;

[0033]FIG. 6 is a partial enlarged front view showing assembled state of the slide cushion unit shown in FIG. 5;

[0034]FIG. 7 is a partial cross sectional view taken along line VII-VII of FIG. 6;

[0035]FIG. 8 is an exploded perspective view of a cover assembly of the vehicular impact absorbing apparatus of FIG. 1;

[0036]FIGS. 9A to 9C are side views schematically illustrating cushioning operation of the apparatus according to the present invention;

[0037]FIGS. 10A and 10B are partial plan sectional views showing energy absorbing operation of the elide cushion unit of this invention;

[0038]FIG. 11 is a cross-sectional view of a vehicular impact absorbing apparatus according to another embodiment of the present invention; and

[0039]FIGS. 12A and 12B are plan views schematically showing an example of installation of the vehicular impact absorbing apparatus according to the present invention, each of which are installed in front of a branch road and an end of a median divider, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] This invention will be described in further detail by way of exemplary embodiments with reference to the accompanying drawings.

[0041] Referring to FIG. 1, there is shown a safety guard including a vehicular impact absorbing apparatus according to the present invention. The impact absorbing apparatus is covered with a cover assembly 70, which includes a front cover 72, a middle cover 71, and a rear cover 73. The covers 71, 72 and 73 are adapted to telescope over one another in an axial collapse. The details of the cover assembly 70 will be described hereinafter with reference to FIG. 8.

[0042] As shown in FIGS. 2 and 4, the vehicular impact absorbing apparatus includes a plurality of cushion units 30 arranged in the form of an array. The cushion units 30 are to absorb vehicular impacts in a more effective way. Each cushion unit 30 has a slider 20 movably mounted onto a guide rail 10, which is fixed to the ground. The guide rail 10 is provided with a group of cushion pins 40 fixed across the guide rail 10. Each group of cushion pins 40 is disposed at a predetermined intervals alongside the guide rail 10. The apparatus further includes a stopper 50 provided at the rear end of the guide rail 10 and a pair of side fences 60 provided alongside the cushion units 30. The side fence 60 is comprised of a plurality of retractable bars 61.

[0043] The guide rail 10 is formed by a hollow rectangle metal tube and is provided at its upper center surface with a guide slit 11 formed along the length thereof. Also, the guide rail 10 has a plurality of mounting plates 12 provided along both sides thereof at an intervals so as to fix the guide rail 10 on the ground “R” by an anchor bolts 13.

[0044] Further, the guide rail 10 is formed with a plurality of fastening holes 14 for receiving the cushion pins 40. The fastening holes 14 is formed in two rows such that the holes 14 in each row to cross each other. This will allow the cushion pins 40 to be densely disposed within the designated section of the guide rail 10.

[0045] Preferably, each cushion pin 40 consists of a bolt 41 and a nut 42. The number of cushion pin 40 as well as its diameter is determined by considering the amount of expected impact energy and allowable shearing stress of the material.

[0046] Preferably, as shown in detail in FIG. 5, the guide rail 10 is manufactured from a pair of channel-type steel frames 15 in such a way that the frames 15 faces each other with a desired space and are fixed to the mounting plates 12 by a welding process.

[0047] Preferably, as shown in FIG. 4, the guide rail 10 is provided in parallel pairs having a desired interval, so that they stably support the cushion units 30 thereon and double the amount of cushion pins 40 being provided in the guide rail 10. With this, the cushion effect is increased enough to reduce the size of the cushion unit array to almost half of its longitudinal length, as compared to the one without the cushion pins 40.

[0048] Inside the guide rail 10, the slider 20 is movably mounted at a predetermined intervals. As apparent in FIGS. 5 to 7, the slider 20 is formed into an I-beam member having a web 21 and a pair of flanges 22, 23 formed at upper and lower ends of the web 21. The web 21 of the slider 20 is inserted into the guide slit 11 of the rail 10, with the upper flange 22 being placed over the outer side of the guide rail 10.

[0049] Referring to FIGS. 6 and 7, the slider 20 is provided at its front and rear portion a pair of anti-shaking members 24 which pass through the web 21 of the slider 20. The top portion of each anti-shaking member 24 abuts against the inner top surface of the guide rail 10.

[0050] The anti-shaking member 24 is preferably made from a bolt and nut. However, the anti-shaking member 24 may have other forms, for example, a pin, a roller and so on.

[0051] The anti-shaking member 24 prevents up-and-down movement of the slider 20 when a vehicular impact is applied to the cushion unit 30.

[0052] Referring again to FIG. 6, there is shown a pair of bolt heads 39 a placed between the lower sides of the upper flange 22 of the slider 20 and the upper surface of the guide rail 10. The bolt 39 couples up the slider 20 to the cushion unit 30.

[0053] The cushion unit 30 includes a base plate 31 mounted on the top portion of the sliders 20, a pair of supports 32 fixed to the base plate 31 and vertically extended along the side portion of the cushion unit 30, a cushion element 33 loaded onto the base plate 31, a holding cover 34 for holding the cushion element 33 in the base plate 31.

[0054] The base plate 31 is formed into a rectangle steel plate, with its corner portion being laid and fixed to the upper flange 22 of the slider 20 by bolts 39 a and nuts 39 b (See FIG. 5). The axial length of the base plate 31 is determined such that a part of the cushion element 33 is protruded from both edges of the base plate 31.

[0055] Preferably, a reinforcing plate 31 a is interposed between the lower side of the base plate 31 and the upper flange 22 of two sliders 20. Thus, the bolt head 39 a fixed to the upper flange 22 of slider 20 can be in contact with the upper surface of the guide rail 10.

[0056] A pair of vertical supports 32 is placed on both sides of the base plate 31, for supporting the cushion element 33. The support 32 is formed by X-shaped crossing plates 32 a having a desired longitudinal length. The end of each plate 32 a is formed with a bending portion 32 b, for reinforcing the strength thereof. The support 32 may have other appropriate forms to receive the cushion element 33.

[0057] The cushion element 33 is preferably formed by a stack of worn tires 33 a placed around the support 32. The cushion element 33 can be made of a resilient material such as rubber, polyurethane and the like. However, worn tire prevails over other materials since it is excellent in elasticity and a useful recyclable material.

[0058] The holding cover 34 is comprised of a pair of channel-shaped unit covers 35 and a coupling plate 36. The holding cover 34 is fixed to both sides of the base plate 31 such that the cover 34 partly surrounds the cushion element 33 to protrude a part of front and rear portions thereof. The coupling plate 36 connects upper portion 35 a of the unit cover 35 to each other. The lower portion 35 b of each unit cover 35 is placed between the base plate 31 and the reinforcing plate 31 a to be joined thereto by the bolt 39 a and nut 39 b. Also, the upper portion 35 a of each unit cover 35 is coupled to the coupling plate 36 and then the base plate 31 by a stay bolt 37, which is passing through one compartment of each support 32.

[0059] As can be seen in FIG. 5, one end of the stay bolt 37 is fixed to the base plate 31 and the other end to the coupling plate 36. With this, the cushion element 33 can be stably supported by the holding cover 34. Instead of the stay bolt 37 which is crossing the support 32, a short bolt can be integrally formed at the top and bottom portions of the support 32 by welding.

[0060] Particularly, the upper portion 35 a of each unit cover 35 is sized such that its width is shorter than that of the lower portion 35 b thereof, so that the exposing area of the cushion element 33 around the upper portion 35 a of unit cover 35 is larger than that of the lower portion 35 b. This will allows the cushion element 33 to have a margin for absorbing more impacts when all of cushion units 30 are compressed to face each other by a vehicular impact.

[0061] At the side portion 35 c of the unit holding cover 35, a plurality of guide tunnels 38 are horizontally provided to movably insert a side bar 61 of the side fence 60, which will be described hereinafter. Further, the above and below outlines of the guide tunnels 38, and brackets 38 a, 38 b are provided to support the outer cover 70.

[0062] The above guide tunnels 38 and brackets 38 a, 38 b can be made in the form of separate unit and then fixed to the side portion 35 c of the unit cover 35 by welding. Also, they can be formed into a corrugated integral assembly and welded to the side portion 35 c.

[0063] As shown in FIG. 7, a group of cushion pins 40 are mounted to the guide rail 10 such that they are disposed at a predetermined intervals alongside the guide rail 10. The cushion pins 40 are arranged in two rows, corresponding to the fastening holes 14 formed in the guide rail 10. As mentioned before, the cushion pins 40 in each row are placed to cross each other. This allows the cushion pins 40 to be densely disposed in the designated section of the guide rail 10. Every group of cushion pins 40 serially cushion vehicular impacts as the cushion units 30 collapses axially.

[0064] Referring to FIG. 3, the widths b₁, b₂, . . . b₅ of each holding cover 34 are determined such that they are gradually decreased as proceeding to rearward direction (b₁>b₂>b₃>b₄>b₅). This is provided for a sufficient installing space for a group of cushion pins 40 and a reduced total length of the cushion unit array. As a result, the safety guard can be adequately installed in a limited area such as a ‘safety zone’ which is in front of a roadway branch, for example.

[0065] Accordingly, the size of the exposed portions of each cushion element 33 is increased as they proceed to rearward direction, which allows cushion element 33 to have an increased amount of elastic deformation. This contributes to a smooth absorption of the kinetic energy of an impacting vehicle and minimizes shock for the passenger.

[0066] Also, considering that the kinetic energy of an impacting vehicle is decreased as it proceeded to rearward direction, it is determined that the spaces s₁, s₂, . . . s₄ between each cushion unit 30 are gradually decreased as they proceed to rearward direction (s₁>s₂>s₃>s₄), and the amount of the cushion pins 40 as well. As a result, the total length of the cushion unit array can be reduced.

[0067] On the other hand, the front cushion unit 30 a is comprised of two cushion units 30, incorporating into a unit body. This is because the front cushion unit 30 a will receive the maximum kinetic energy at the initial vehicular impact. This allows for a stable resistance to the initial impact and a smooth intrusion into the subsequent cushion unit.

[0068] Behind the last cushion unit, the stopper 50 is provided to limit the rearward movement of the cushion unit array. The stopper 50 is preferably formed into a truss type steel structure. As shown in FIG. 2, the stopper 50 includes a pair of vertical posts 51 which are supported by a slant support bar 52, respectively. A pair of connecting bars 53 are horizontally joined between the support bars 52. The post 51 and the slant support bar 52 are fixed to the ground by an anchor bolt 54.

[0069] Referring again to FIG. 2, the side fence 60 is comprised of a plurality of side bars 61 horizontally disposed between the front cushion unit 30a and the stopper 50. The side fence 60 is provided to cushion a lateral vehicular impact, which prevents the impacting vehicle from being moved into the region between the cushion units 30 and redirects the impacting vehicle without sending it back into traffic at a steep angle, acting like a guard rail.

[0070] In an axial vehicular impact, the side bars 61 should be compressed alongside the cushion units 30 moving rearward. To this end, each of the side bar 61 consists of three separate bars 62, 63 and 64, coupled to one another in a telescopic form. The side bar 61 is inserted into the guide tunnels 38 provided at each side portion of the holding covers 34. Each of the front separate bar 62 is fixed to a vertical coupling bar 65 provided at both sides of the guide tunnel 38 of the front cushion unit 30 a, by a bolt 67. Further, each of the rear separate bar 64 is fixed to the vertical post 51 of the stopper 50 by a bolt 66.

[0071] In such a aide bar 61, the length of the rear separate bar 64 is determined to correspond to the extent of the cushion unit assembly, from the post 52 of the stopper to the front cushion unit 30, that fully compressed by an axial vehicular impact. This will prevent the side bar 61 from intruding into the impacting vehicle.

[0072] Referring to FIG. 8, the vehicular impact absorbing lo apparatus of this invention preferably includes an outer cover 70, which can be compressed simultaneously with the cushion units 30 and allows for a good appearance of the safety guard. The outer cover 70 consists of a plurality of middle covers 71 for covering the cushion unit array, a front cover 72, and a rear cover 73 for covering the stopper 50. These covers are coupled to telescope over one another, so that each unit of middle cover 71 can be overlapped successively and retracted to the rearward middle cover.

[0073] To this end, each of the middle cover 71 is fixed to the bracket 38 a of the corresponding cushion unit 30 by a screw 74, and the front cover 72 is fixed to the front middle cover. The rear cover 73 is also fixed to the rearward middle cover by screws. In this embodiment, the middle cover 71 is horizontally divided into at least two panels 71 a, 71 b which acts as a fender panel. To couple the divided panels to each other, one of the panels 71 a, 71 b is provided at the top end part thereof with a rise portion 75, on which the other top end part is fitted. The panels 71 a, 71 b are coupled to each other by screws 76.

[0074] Further, a guide bead 77 is outwardly formed at the upper portion of the middle cover 71 to secure a space for the top end of the stay bolt 37. Also, a plurality of reinforcing beads 78 are outwardly formed at each side of the middle cover 71.

[0075] The surface of the front cover 72 is attached with a safety sign 72 a, preferably made of a light-reflective material. The rear cover 73 is provided at its center portion with a door 73 a for communicating with a box “B” placed on the space of the stopper 50. The box “B” receives for example sand bags and the like.

[0076] The outer cover or cover assembly 70 may be manufactured from high strength synthetic resins, such as a fiber glass reinforced plastics (FRP).

[0077] The operation of the above vehicular impact absorbing apparatus will be described with reference to FIG. 9A to FIG. 10B. The vehicular impact absorbing apparatus of this invention is installed on a site with the state as shown in FIG. 3 The cushion units 30 are positioned with maintaining a predetermined space s₁, s₂, s₃ and s₄ relative to each other. The side bar 6l and the outer cover 70 are at their fully extended state.

[0078] In this state, when the front of the cover assembly 70 in collided with a vehicle “V”, as shown in FIG. 9A, the foremost cushion unit 30 a is tilted rearward (shown as imaginary lines) and the exposed portion of the cushion element 31 is elastically deformed, to absorb the initial vehicular impact, which is considered as the largest kinetic energy of the impact.

[0079] At the same time, as the foremost cushion unit 30 a moves rearward by the remainders of the kinetic energy, the sliders 20 joined to the bottom portion of the cushion unit 30 a begin to move quickly in the rearward direction.

[0080] As the sliders 20 moves fast rearward along the guide rail 10, the cushion pins 40 mounted over the designated apace between the foremost cushion unit 30 a and the subsequent cushion unit 30 will be broken one by one, by colliding with the web 21 of the slider 20, as shown in FIGS. 10A and 10B.

[0081] The cushion pins 40 will resist against the striking force of the slider 20 due to its impact strength, and finally be broken. This process contributes to a smooth absorption operation of the present invention. Furthermore, since the cushion pins 40 are mounted in a group at every location between the subsequent cushion units 30, the kinetic energy of the impacting vehicle will be gradually decreased by breaking of the cushion pins 40.

[0082] Thus, an amount of kinetic energy can be absorbed by a group of cushion pins 40 and the speed of the impacting vehicle will also be decreased.

[0083] As shown in FIG. 9b, as the foremost cushion unit 30 a moved to the subsequent cushion unit 30 while breaking the cushion pins 40 located at the front area, the exposed cushion element 33 of the cushion unit 30 is also elastically deformed by the successive vehicular impact. This cushion unit 30 is also begin to move quickly in the rearward direction along the guide rail 10. Accordingly, the cushion pins 40 mounted over the designated space between the subsequent cushion units 30 will be broken serially with a resistance against the strike of the second slider. With this, the kinetic energy of the impacting vehicle and the speed of the impacting vehicle is further decreased.

[0084] Lastly, as shown in FIG. 9C, as all the cushion units 30 moves closer to the rear end portion of the cushion unit array, the movement of cushion units 30 are restrained by the stopper 50 with each cushion unit 30 being closer to one another in the elastically deformed state. Thus, the kinetic energy of the impacting vehicle will be vanished and the impacting vehicle will be halted.

[0085] In this operation, since the widths b₁, b₂, . . . b₅ of each holding cover 34 of the cushion units 30 are gradually decreased and the exposed portions of the cushion elements 33 are gradually increased as they proceed rearward direction, the amount of compress deformation of the cushion elements 33 will be increased as the kinetic energy of an impacting vehicle and the vehicle speed are decreased, by successive cushion and deceleration of the vehicular impact, thereby effectively absorbing the minute impact energy and minimizing the effect of the impact on the passenger.

[0086] Further, since the upper portion 35 a of the unit holding cover 35 is sized to have shorter width than the lower portion 35 b thereof, and the exposing area of the cushion element 33 around the upper portion 35 a is larger than that of the lower portion 35 b, the cushion element 33 can be further compressed in the full retraction state of the cushion units 30, thereby absorbing a marginal impact energy.

[0087] Therefore, according this embodiment, the kinetic energy of the impacting vehicle can be nearly removed at the time all the cushion units 30 moved to the rear end and are halted by the stopper 50. This will minimize injury of passenger and reduce damage of the impact absorbing apparatus itself as well as the impacting vehicle.

[0088] Particularly, since a group of cushion pins 40, disposed at short intervals within a designated section, are bent to be broken upon the strike of the slider 20, the sliders 20 are interfered by the broken cushion pins 40 after passing through the cushion pins. Therefore, it is possible to prevent spring back of the cushion elements 33 due to the repulsive power thereof and to stop the impacting vehicle. This will protect the impacting vehicle against the secondary collision with another vehicle.

[0089] Further, since the cushion units 30 are elastically deformed with its cushion elements 33 as they moves along the guide rail 10, the cushion units 30 may be reused but with replacing the broken cushion pins 40. This will contribute to saving cost for maintenance and repair.

[0090] Turning to FIG. 11, there is shown a vehicular impact absorbing apparatus according to another embodiment of this invention.

[0091] In this embodiment, a cushion unit 30 has only one cushion element 33, which consist of a stack of worn tires as like the previous embodiment. Thus, the width of the cushion units is narrower (almost half) than that of the previous embodiment. This arrangement can be applied to the location where the vehicle speed is restricted to a low speed and the kinetic energy of the impacting vehicle is relatively small. The rest components of this embodiment are the same as those of the first embodiment. Therefore, the detailed description will be omitted for brevity's sake, with denoting the same reference numerals of the same components described in the first embodiment.

[0092]FIG. 12A shows an example of installation of the vehicular impact absorbing apparatus according to this invention. The safety guard “C” includes the above impact absorbing apparatus, which is installed in front of a branch road.

[0093]FIG. 12B shows that are installed in front of an end of a median divider “W”, between both ends of the guide rails to constitute a part of the median divider “W”. In this case, H-beams fixed adjacent each end of the guide rails may be used as a stopper.

[0094] As described above, according to the vehicular impact absorbing apparatus of this invention, it is possible to effectively absorb the kinetic energy of an impacting vehicle through an appropriate elastic deformation of the cushion units and a successive shear of the cushion pins.

[0095] Further, since the sliders are interfered by the broken cushion pins after passing through the cushion pins, it is possible to prevent spring back of the cushion elements due to the repulsive power thereof and to stop the impacting vehicle, thereby protecting the impacting vehicle against the secondary collision with another vehicle.

[0096] Furthermore, since the amount of compress deformation of the cushion elements is increased as proceeding to rearward, a successive cushion and deceleration of the vehicular impact is possible, thereby absorbing the minute impact energy and minimizing the effect of the impact on the passenger.

[0097] Further, since the cushion units are elastically deformed as they moves along the guide rails, the cushion units can be reused and only replacing of the broken cushion pins is required. This contributes to reduction in maintenance and repair cost. In addition, the above allows for a reduced total length of the cushion unit array and the safety guard can be properly installed in a limited area.

[0098] Further, since worn tires are used as the cushion element of each cushion unit, the cost for manufacturing and repair can be reduced. After collision, the broken part for example the cushion pins can be simply replaced, which contributes to saving cost for maintenance and repair.

[0099] Although preferred embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as defined in the accompanying claims. 

What is claimed is:
 1. A vehicular impact absorbing apparatus, comprising: a tubular guide rail having a guide slit longitudinally formed at the upper part of the guide rail, the guide rail being fixed to the ground; a plurality of sliders movably mounted in the guide rail at a predetermined intervals, the upper part of each slider being laid on the upper part of the guide rail through the guide slit; a plurality of cushion units mounted on the upper part of each slider, each cushion unit being elastically deformed by vehicular impacts with retracting alongside the guide rail; a group of cushion pins mounted across the guide rail at a predetermined intervals between the sliders, the cushion pins being broken serially by the slider retracting rearward; a stopper installed around the rear end of the guide rail for stopping the retraction of the cushion unit; and a side fence retractably mounted alongside the cushion units, the one end of the side fence being fixed to the stopper and the other to the front cushion unit.
 2. The apparatus as set forth in claim 1, wherein the cushion unit includes a base plate mounted on the top portion of the slider, the base plate having a supports fixed thereto and vertically extended along the side portion of the cushion unit; a cushion element loaded onto the supports of the base plate with a part of the cushion element being protruded from the front and rear side of the base plate; and a holding cover coupled to the below portion of the base plate and the top portion of the support, for surrounding both sides of the cushion element,
 3. The apparatus as get forth in claim 2, wherein the widths of the base plate in each cushion units are gradually decreased and the protruded portions of the cushion element are gradually increased as they proceed rearward direction.
 4. The apparatus as set forth in claim 2, wherein the cushion element includes a stack of worn tires being laid around the support.
 5. The apparatus as set forth in claim 1, wherein the guide rail is formed with a plurality of fastening holes for receiving the cushion pins, and the fastening holes is formed in two rows such that the holes in each row to cross each other.
 6. The apparatus as set forth in claim 1, wherein the spaces between each cushion unit are gradually decreased as they proceed to rearward direction, and the amount of the cushion pins are gradually decreased as well.
 7. The apparatus as set forth in claim 1, wherein the slider is formed into an I-shaped member having a web and a pair of flanges formed at upper and lower ends of the web, the web being inserted into the guide slit of the guide rail with the upper flange being placed over the outer side of the guide rail, and wherein the slider includes at least two anti-shaking members at the front and rear portion thereof, the top portion of anti-shaking member abuts against the inner top surface of the guide rail for preventing up-and-down movement of the slider.
 8. The apparatus as set forth in claim 1, wherein the side fence includes a plurality of side bars, each of which consists of three separate bars coupled to one another in a telescopic form.
 9. The apparatus as set forth in claim 8, wherein the holding cover of the cushion unit is provided at both side portions thereof a plurality of guide tunnels, for movably receiving the aide bar of the side fence.
 10. The apparatus as set forth in claim 1, further comprising an outer cover for enclosing the components of the apparatus.
 11. The apparatus as set forth in claim 10, wherein the outer cover includes a plurality of middle covers coupled to each cushion unit for covering the cushion units, a front cover coupled to the foremost middle cover for covering the front portion of the foremost cushion unit, and a rear cover for covering the stopper, the covers being coupled to telescope over one another.
 12. The apparatus as set forth in claim 11, wherein the stopper is formed into a truss type steel structure, the stopper including a pair of vertical posts supported by a slant support bar fixed to the ground, and a door for communicating with a box B placed on the space formed therein.
 13. The apparatus as set forth in claim 2, wherein the axial width of the holding cover is determined to be smaller than that of the base plate.
 14. The apparatus as set forth in claim 1, wherein the guide rail is comprised of at least two guide rails arranged in parallel to each other.
 15. The apparatus as set forth in claim 2, wherein the cushion element is comprised of at least two cushion elements arranged in a row. 